This invention relates to the field of surgical devices. More specifically, this invention relates to an improved surgical device for inserting tissue fasteners.
The surgical device of the invention is particularly but not solely intended to be used in repair surgery of traumas of soft and/or tough tissues containing fibrous structures, such as knee meniscal tissues.
In the past, doctors have effectively treated internal ruptures and tears of tissue by suturing, often with bioabsorbable sutures. For instance, this technique for treating ruptures of meniscal tissue in the knee has been described in N. A. Palmeri, T. F. Winters, A. E. Joiner and T. Evans, xe2x80x9cThe Development and Testing of the Arthroscopic Meniscal Staplexe2x80x9d, Arthroscopy, Vol. 5, No. 2, 1989, p. 156. However, suturing, particularly arthroscopic suturing, has many drawbacks. It is a complicated and tedious technique where risks for the patient are significant because of the danger to vessels and nerves. Additionally, the suturing of a ruptured meniscus leaves a single or several loops of sutures on the surface of the meniscal tissue, which can irritate joint cavity tissues. Therefore, for a long time surgeons have desired an absorbable fixation device, like a staple or fastener, which has the advantages of absorbable suturing techniques but which can be used more rapidly and safely than sutures.
Tissue fasteners have been developed, including fasteners that may be inserted entirely below the surface of the tissue that is being treated, thereby preventing any irritation that may result from the portion of the fastener remaining above the ruptured tissue surface. These fasteners are described in detail in U.S. patent application Ser. No. 08/887,130, entitled SURGICAL FASTENER FOR TISSUE TREATMENT, by Tormala, et al., which is hereby incorporated by reference.
Accordingly, there is a need for surgical devices to insert these fasteners. Such devices must be accurate, reliable, quick, easily positioned and operated within a patient, and cost effective. It is important to reduce the invasiveness and length of any surgery to repair internal ruptured tissues.
Certain previous devices for installing tissue fasteners require that the fasteners be manually inserted into the patient. It is time consuming for fasteners to be inserted with such devices because the surgeon has to, for instance, repeatedly tap the fastener until it is fully inserted into the patient. Further, because of the manual propulsion of the fastener, it is impossible with such devices to ensure that each fastener receives a measured, consistent amount of force to drive it into the patient.
Other previous devices for installing tissue fasteners have used mechanical techniques for propelling fasteners into a patient, but have only had the capability of holding one fastener at a time, thereby requiring the surgeon repeatedly during an operation to remove the device from the patient, load another fastener, and reinsert the device into the patient. It is important that a surgeon be able to insert these fasteners precisely. Thus, it is time consuming to remove the device from the patient and then reposition it so that it is in position to deliver a fastener exactly where needed. Having to do so increases the length and difficulty of the surgery, and the concomitant risk of infection or other complications to the patient.
There have also been devices for installing tissue fasteners that are capable of holding a fixed number of fasteners. These devices, however, are self contained and are not capable of receiving additional fasteners. These devices also do not provide enough flexibility to the surgeon concerning the number of fasteners used during the operation because in many cases, the surgeon will not know how many fasteners are needed until the operation has begun. For instance, if the device holds six fasteners, yet the operation demands eight fasteners, after the sixth fastener, the surgeon must remove the device, dispose of it, and insert a second new device containing another six fasteners into the patient. This device must then be disposed of after only two of its six fasteners have been inserted into the patient. The use of such a device increases the length and difficulty of the surgery, because the surgeon must change devices in the middle of the operation. This poses an added risk, because the second device could have slightly different operating characteristics than the first device to which the surgeon has become accustomed. Further, such devices are inefficient and costly because a single surgery could require the use of more than one delivery device. This is compounded by the fact that fasteners in the device that are not used are disposed of along with the delivery device.
Further, none of these devices provide a method for inserting fasteners in such a way that no part of the fastener remains on or above the surface of the tissue being treated. It is advantageous to be able to insert fasteners entirely below the surface of the tissue being treated to avoid any irritation or inflammation that could occur when other tissues rub against that portion of the fastener on or above the tissue that has been treated.
An additional problem with previous devices in this field is that their conduits are invariably straight or invariably curved. At times, a surgeon is required to use these devices to repair tissue that is difficult to reach. Further, a surgeon must precisely insert many different fasteners at different angles. Thus, at times, a straight conduit may be preferred, while at other times, it may be difficult for the surgeon to properly approach the tissue that is to be treated with a straight conduit and a curved conduit may be preferred. Presently, in such a situation, a surgeon would need to use entirely separate devices with different conduits to insert the different fasteners. Using entirely different devices during an operation poses the same risk as described previouslyxe2x80x94the second device could have slightly different operating characteristics than the first device to which the surgeon has become accustomed. This increases the risk that a fastener will not be optimally inserted. Further, such devices are inefficient and costly because a single surgery could require the use of more than one delivery device.
Thus, there is a desire in the field for a device to install tissue fasteners that is capable of holding more than one fastener and capable of receiving additional fasteners during an operation without requiring the surgeon to remove the device from the patient. With such a device, the surgeon may use as many fasteners as he requires, while only having to insert the device into the patient once. Also, no fasteners are wasted. This reduces the length, difficulty, and cost of the procedure. Further, there is a desire in the field for a device that is capable of inserting a fastener entirely within the tissue to be treated so that no part of the fastener remains above or on the surface of the tissue. Such a device reduces the likelihood of irritation and inflammation of the treated area. Also, there is a desire in the field for a device that accurately and reliably inserts fasteners. Lastly, there is a desire in the field for a device with a conduit that can be curved or straight, to allow the surgeon to more easily insert the fastener properly into the patient.
Thus, it is an object of the present invention to provide a device for installing tissue fasteners that allows a minimally invasive method for repairing torn or ruptured tissue.
It is further an object of the present invention to provide a device for installing tissue fasteners that is capable of holding more than one fastener and of receiving additional fasteners during an operation without requiring the removal of the device from the patient.
It is further an object of the present invention to provide a device for installing tissue fasteners that is capable of inserting a fastener entirely within the tissue being treated, so that no part of the fastener remains above or on the surface of the treated tissue.
It is further an object of the present invention to provide a device for installing tissue fasteners that may quickly and easily be positioned within a patient.
It is further an object of the present invention to provide a device for installing tissue fasteners that accurately and reliably inserts tissue fasteners into a patient.
It is further an object of the present invention to provide a device for installing tissue fasteners that is cost effective.
These objects and others are attained with the device of the present invention, as described below.
The device of the present invention is designed for repairing a tear in soft and/or tough tissue of a patient, such as a tear in the meniscus of the knee.
The device has a conduit, such as a cannula, that may be easily inserted into the patient and through which the fastener is delivered to the patient. This conduit is aligned with a seat for holding a fastener and a means for pushing a fastener, such as a piston, so that the pushing means is capable of pushing a fastener from its seat, through the conduit and into the patient. In a preferred embodiment of the invention, the shape of the conduit exactly matches the shape of the cross-section of the fastener so that the surgeon may more accurately direct the angle and location at which the fastener enters the patient. In another preferred embodiment, the pushing means may be made to slowly push the fastener from its seat and through the conduit until the distal end of the fastener contacts the surface of the tissue to be treated at the end of the conduit. At that time, the pushing means may be made to accelerate rapidly, thereby inserting the fastener into the tissue being treated. An advantage of this embodiment is that the fastener is less likely to become jammed in the conduit while being pushed slowly through it. Further, the conduit, piston, and fastener are subject to less wear, which helps to ensure proper functioning of the device during an operation.
The seat for holding fasteners is capable of holding a magazine containing one or more fasteners. When inserted into the seat, the magazine may be positioned so that a fastener is aligned with the pushing means and the conduit leading to the patient. Once a fastener has been inserted into the patient, the magazine may be manually positioned so that another fastener is shifted into position to be inserted. In one embodiment of this invention, the magazine may have means, such as a spring, for automatically moving a fastener into position for insertion once a fastener has been inserted.
The magazine may be easily removed from the seat during an operation, so that it may be replaced with a magazine containing one or more fasteners without requiring the conduit to be removed from the patient. Alternatively, the same magazine could be removed, refilled with one or more additional fasteners, and reinserted into the seat, without requiring the removal of the conduit from the patient. In yet another embodiment of the invention, when the magazine is positioned to allow the insertion of one fastener into the patient, a portion of the magazine is accessible to allow the insertion of one or more additional fasteners into the magazine. In this fashion, additional fasteners may be added to the magazine without requiring its removal from the device or the removal of the conduit of the device from the patient.
In a preferred embodiment of the invention, the conduit or barrel of the device is easily removable from the rest of the device. This allows the same device to be used during an operation with differently shaped conduits, depending upon the location and condition of the tissue being treated. Thus, for instance, during the same operation, the surgeon could insert fasteners through a straight conduit, then easily replace the straight conduit with a curved conduit and continue the operation without the need for an entirely new device.
In another preferred embodiment of the invention, the pushing means, e.g., piston, of the device is capable of extending slightly beyond the end of the conduit that is in contact with the tissue being treated. Such extension of the pushing means ensures that it pushes the fastener until it is embedded entirely within the tissue being treated, with no portion of the fastener remaining on or above the surface of the tissue being treated.
In yet another preferred embodiment of this invention, the device has a safety mechanism that helps prevent the surgeon from inadvertently shooting the fastener into the patient until the proper moment. This mechanism works in conjunction with the triggering mechanism so that the means for propelling the pushing means rapidly into the fastener cannot be actuated until both the triggering means and the safety mechanism are actuated simultaneously.